Make version management easy

Fabric configuration that's currently edited manually through the API/DB has no UI — e.g. which Harper versions are published, and per-org version scoping ([central-manager#580](https://github.com/HarperFast/central-manager/issues/580)). Routine changes like exposing a version for one org's upgrade need an engineer to add and later remove entries by hand ([Slack thread](https://harperdb.slack.com/archives/C03DLGGN43G/p1786622978640789?thread_ts=1786622978.640789&cid=C03DLGGN43G)).

Build an admin-only section in studio to view and edit these configuration tables.

- Visible to fabric admins only.
- First table: available Harper versions, global and per-org (pairs with #580).
- Enumerate the remaining configuration tables when picking this up — the ask was a UI around all of them.

No files, tests, or entry points are named. Start by locating the existing admin-only areas in studio and enumerate the configuration tables exposed by the API or database; done means fabric admins can view and edit all identified tables, beginning with global and per-org Harper versions, while other users cannot access them.

Written by the indexing model from the issue text.